1. Field of the Invention
The present invention relates to a track renewal machine extending in a longitudinal direction and movable in an operating direction. The machine comprises a lower tie transport unit extending in the longitudinal direction for transporting new ties, means for laying the new ties associated with the lower tie transport unit, an upper tie transport unit positioned above the lower tie transport unit for transporting old ties, means for receiving the old ties associated with the lower tie transport unit, a ballast receiving means positioned between the means for laying the new ties and the means for receiving the old ties, a ballast distributing means arranged rearwardly of the ballast receiving means in the operating direction, and devices for guiding new rails and laying the new rails on the laid new ties.
2. The Prior Art
Machines of this type are known from U.S. Pat. No. 6,415,720 or Austrian patent No. 353,816, the disclosures of which are incorporated herein by reference. Arranging the transport unit for the old ties above the transport unit for the new ties enables the means for receiving the old ties and the means for laying the new ties as well as the ballast receiving means to be concentrated at one end of the machine. This has the advantage that the machine may be operated selectively in opposite operating directions and also that the machine is relatively short. The ballast receiving means enables the ballast in the cribs to be taken up and to be discharged outside the ends of the ties so that it does not interfere with laying the new ties. Afterwards, the ballast is distributed in a subsequent operating step over the entire width of the ballast bed by a ballast plow.
It is also known to convey the received ballast by a conveyor band to the rear end of the machine for discharge on the track, as shown in U.S. Pat. Nos. 4,774,890, 4,854,243 and 6,450,101, as well as EP 0 775,780 or AT 313,341, the disclosure of which are incorporated herein by reference.